Biotechnology and Proteins Lecture Notes PDF

Dr. Manal Abouelwafa Badr University in Assiut Lecture 4 Biotechnology Department [email protected] 1 Lecture Saturday 2:0 – 4:0 PM Room No. V 301 Assessment : 20% Tests / Reports 10% Midt...

Dr. Manal Abouelwafa Badr University in Assiut Lecture 4 Biotechnology Department [email protected] 1 Lecture Saturday 2:0 – 4:0 PM Room No. V 301 Assessment : 20% Tests / Reports 10% Midterm Exam 10% Oral Exam 60 % End Term Exam Textbooks: 1- Satyanarayana, U. (2005). Biotechnology, Books And Allied (p) Limited. 2- Nair, A. J. (2004). Basics of Biotechnology, Laxmi Publications. 2 UNIT 1: ❑ Genetic Engineering UNIT 2: ❑ Gene cloning and expression UNIT 3: ❑ Nucleic acid blotting and DNA sequencing. UNIT 4: ❑ Applications of genetic engineering. 3 Proteins as Biotechnology Products and … (cDNA) The central dogma 5  Genetic Code The genetic code used by cells as a triplet code, in which every three-nucleotides sequence, or codon, is “read” from a specified starting point in the mRNA. 8 Properties of Genetic Code Codons: Groups of three bases form codons, each standing for one amino acid (or start or stop). Universal: The genetic code is universal, meaning it is the same across different organisms. Non-overlapping: Codons are read in sequence without overlap. Degenerate: Multiple codons can code for the same amino acid. Ordered: Translation of mRNA occurs in the 5′ → 3′ direction. 9  Proteins The name of protein is derived from the Greek word proteios “prime importance or the first kind” this is because proteins are the basis of the cytoplasm of cells and are present in all living organisms. Proteins are the most abundant macromolecules in living cells and constitute 50% or more of their dry weight. 11  Proteins are polymers of α-amino acids. Proteins are synthesized from only 20 amino acids, known as the common amino acids. Amino acids are formed mainly of carbon, hydrogen, oxygen and nitrogen. Nitrogen is a characteristic component of proteins forming about 16% of their weight (i.e. 100 g of protein contains 16 g of nitrogen) 12  Biological Importance of Protein… Plasma membrane proteins (channel, carrier, pump proteins) regulate the transfer of many substances across the cell membrane All receptors are protein in nature All enzymes are proteins in nature All antibodies (immuno-globulins) are proteins in nature. Some hormones are proteins in nature (e.g. insulin and growth hormone). 13  Biological Importance of Protein (cont.) Some proteins are protective, e.g. Keratins (skin, hair and nails) make the skin resistant to chemicals Some proteins are supportive, e.g. Collagen; the most abundant protein in animals. Hemoglobin is a protein carries O2 in blood. Actin and myosin are contractile proteins found in muscle cells and responsible for muscular contraction. Amino acids (AA) are converted to other nitrogenous substances of great physiological importance (e.g. creatine, histamine, heme, purines and pyrimidines). 14  Biological Functions of Protein 1. Catalytic function: Nearly all chemical reactions in biological systems are catalyzed by specific enzymes. 2. Transport and storage: …..For example; Hemoglobin transports oxygen in blood. Myoglobin carries and stores oxygen in muscle. Albumin transports free fatty acids in blood. 3. Coordinated motion: Actin and myosin are contractile proteins in muscle. 15  Biological Functions of Protein (cont.) Structural and mechanical support: - Collagen (a fibrous protein in skin and bone). Defense function: - Clotting factors (prevent loss of blood) - - Immunoglobulins (protect against infection). Generation and transmission of nerve impulses: - Receptor proteins (neuro-transmitters, e.g. Acetylcholine. Control of growth and differentiation: - such as insulin and thyroid-stimulating hormone. 16  Polypeptide backbone is the repeating sequence of the C and N atoms linked by peptide bonds. The side chain or R group gives the amino acid its unique property and is not part of the backbone or the peptide bond. 17 Proteins, are biomolecules composed of amino acids that joined together with a specific covalent bond called “peptide bond”, which participate in nearly all cellular activities. 18  Structural organization Each polypeptide assumes at least three levels of structural organization: primary, secondary and tertiary structure Proteins which posses more than one polypeptide chain in their molecule also posses a fourth structure called quaternary structure. 19 Primary structure The sequence of amino acids residues along the peptide is called primary structure 20  Secondary structure X-rays diffraction on protein crystals shows that polypeptide tend to twist or coil upon themselves The folding of the polypeptide chain into specific coiled structure held together by H-bonds is called secondary structure of protein. It may take one of the following forms: A. Alpha- helix B. Beta pleated sheets 21  Tertiary structure It means the overall conformation of a polypeptide, it’s the three dimensional shape of a protein It’s formed by non-covalent interactions between the R groups within the protein The common features of protein tertiary structure reveal much about the biological functions of the proteins and their evolutionary origins 22  Quaternary structure It’s formed by the association of several protein chains or subunits into a closely packed arrangement. Each of the subunits has its own primary, secondary, and tertiary structure. The subunits are held together by hydrogen bonds and van der Waals forces between nonpolar side chains. 23  Protein folding Protein's shape is determined by the sequence of the amino acids The final shape is called the conformation it has the lowest free energy possible. Proteins must fold to assume their functional state. Folding can be spontaneous or facilitated by proteins called chaperones Chaperones are small proteins that help guide the folding and can help keep the new protein from associating with the wrong partner. 24  Types of proteins Proteins are classified according to their shape depending on the axial ratio of the proteins i.e. length divided by width of the protein into: A. Globular protein B. Fibrous protein 25 Complementary DNA Complementary DNA (cDNA) is synthesized in the laboratory from messenger RNA). cDNA is not genomic DNA , because the transcript of genomic RNA has been processed (i.e., it lacks promoters and introns). The enzyme Reverse Transcriptase is used to synthesize double-stranded DNA that is a complementary copy of the mRNA. 27  Normal transcription Reverse transcription is the Reverse - shared Nobel involves transcription of single Transcriptase Prize in synthesis of RNA stranded RNA into double was discovered Physiology or from DNA. stranded DNA With the by Howard Medicine in help of the enzyme Reverse 1975 for their Temin and Transcriptase. discovery. Baltimore in 1970 independently 28  Reverse transcriptase common in Retrovirus. HIV M-MLV (Moloney Murine Leukemia Virus) AMV (Avian Myeloblastosis Virus) Reverse Transcriptase enzyme includes two activity: DNA polymerase and RNase H 29 1- Proteins as Biotechnology Products: – Are complex molecules built of chains of amino acids – Have specific molecular weights – Have electrical charge that causes them to interact with other molecules Hydrophilic – water loving Hydrophobic – water hating  2- Biotechnology Drugs and other medical applications – Produced through microbial fermentation or mammalian cell culture – Complicated and time-consuming process – Once the method is determined produce large batches of the protein products in bioreactors by growing the host cells that have been transformed to contain the therapeutic gene of interest Cells are stimulated to produce the target proteins through precise culture conditions that include a balance of temp., oxygen, acidity, and other variables At appropriate time the proteins are isolated from the cultures, tested at every step of purification and formulated into pharmaceutically active products. – Must strictly comply with FDA regulations at all stages of the procedure. 3- Screening molecules associated with disease:- - Identify early predictor biomarker proteins to one day aid in diagnosis of specific diseases. - Insulin once had to be harvested from pigs and cows. 4- Applications of Proteins in Industry: – Food processing – Textiles and leather goods – Detergents – Bioremediation. - Some microorganisms have a sticky coat of.. Metallothioneins, proteins that actually capture heavy metals. Biotechnology and Proteins… - Srinibas Kumar (2021), Important Techniques of Biotechnology, https://www.biologydiscussion.com /biotechnology/techniques ‐biotechnology /important‐techniques‐of‐biotechnology‐3‐techniques/15683. - Intro to Biotechnology: Techniques and Applications (2021), https://www.nature.com /scitable/ebooks/intro‐to‐biotechnology‐techniques‐and‐applications‐16570330/cont. - Guide to Biotechnology (2007) Biotechnology Industry Organization